JP2010191305A - A fixing unit and an image forming apparatus provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing unit which reliably peels off paper stuck to a fixing member such as a fixing roller and prevents the fixing member from being damaged, and to provide an image forming apparatus provided with the same. <P>SOLUTION: The fixing unit 18 includes: a fixing belt 52 that is heated by a heater lamp 55a; a pressing roller 54 to be brought into a press contact with the fixing belt 52; and a nip section N formed by the fixing belt 52 and the pressing roller 54 and melt-fixing the toner image that is transferred to the paper P. Furthermore, the fixing unit 18 includes: a peeling member 60 having a gap between a surface of the fixing belt 52 and the pressing roller, and arranged along the longitudinal direction of the fixing belt 52 on the downstream side in the rotational direction; and an adjusting member 70 which is set so that one end of the peeling member 60 in the longitudinal direction is fixed and the other end of the peeling member 60 in the longitudinal direction can be rocked against the surface of the fixing belt 52. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used in an image forming apparatus such as a copying machine, a printer, a facsimile, or a composite machine using an electrophotographic method, and an image forming apparatus including the fixing device. The present invention relates to a fixing device including a peeling member that peels off the toner and an image forming apparatus including the fixing device.

  In an image forming apparatus using an electrophotographic system, a sheet on which a toner image is transferred is passed through a nip portion of a pair of rollers including a fixing roller and a pressure roller, and heating by the fixing roller and pressure between the rollers are performed. Therefore, a fixing device that melts and fixes a toner image on a sheet is widely used. In this fixing device, when the toner image on the paper is melted and fixed, the toner comes into contact with the fixing roller. Therefore, the fixing roller is used by forming a fluororesin with good releasability on the surface. However, even when such a fixing roller is used, the melted toner is soft and has high viscosity, so that it easily adheres to the surface of the fixing roller and the paper may be wound around the fixing roller. Therefore, in order to peel the wound paper from the fixing roller, a sheet-like peeling member is provided on the downstream side in the rotation direction of the nip portion of the fixing roller.

  For example, in Patent Document 1, the paper attached to the surface of the fixing roller is peeled off without damaging the fixing roller. Specifically, a peeling member is disposed downstream of the nip portion between the fixing roller and the pressure roller in the sheet conveyance direction. This peeling member is based on a resin sheet or a metal sheet, a plate-like peeling part, a support piece bent downward at both ends of the peeling part, a fitting hole formed in the support piece, It is comprised from the guide part extended in the both-ends front of the peeling part. The tip of the peeling portion is in non-contact with and close to the fixing roller. The support shaft of the fixing roller is fitted into the fitting hole of the support piece, and the peeling member is rotatably supported. The guide portion is in contact with the fixing roller by the bias of the spring, and as a result, the gap between the tip of the peeling portion and the surface of the fixing roller is made constant at all times. In this configuration, the paper that adheres to and is wound around the fixing roller is peeled off by the tip of the peeling member when the fixing roller rotates.

  However, in the above-described conventional technology, the peeling portion of the resin sheet or the metal sheet is deformed from a predetermined shape by twisting, warping, bending, or the like in mold forming or sheet metal processing. The longitudinal direction of the peeling portion (direction perpendicular to the paper transport direction) needs to be a length corresponding to the paper size, and the flatness of the peeling portion surface is broken by twisting or warping, and the inclination tends to occur. . If the peeling part is mounted in an inclined state, the gap between the peeling part and the fixing roller surface is not constant in the longitudinal direction, and it becomes difficult to peel the paper from the fixing roller with a uniform force across its width direction, resulting in poor peeling. There was a problem that occurred. Further, when the peeling portion is inclined in a direction in contact with the surface of the fixing roller, there is a problem that the fixing roller is damaged.

JP 2003-263064 A (paragraphs [0022] to [0026], FIGS. 3 and 4)

  The present invention has been made to solve the above-described problems, and includes a fixing device that reliably peels off paper attached to a fixing member such as a fixing roller and does not damage the fixing member. Another object of the present invention is to provide an image forming apparatus.

  In order to achieve the above object, the present invention provides a heating rotating member heated by a heat source, a pressure rotating member pressed against the heating rotating member, the heating rotating member and the heating rotating member, and transferred to a sheet. A nip portion for fusing and fixing the toner image formed, and a surface and a gap of one of the heating rotating member and the pressure rotating member, and extending longitudinally downstream in the rotation direction of the one rotating member. A peeling member disposed along the direction, and an adjustment member that fixes one end in the longitudinal direction of the peeling member and is provided so that the other longitudinal end of the peeling member can swing with respect to the surface. It is characterized by providing.

  According to this configuration, even if the peeling member is deformed from a predetermined shape due to torsion or the like in the manufacturing process and tilts in the longitudinal direction of the peeling member, the peeling member is swung by the adjustment member in a direction to correct the inclination. Then, the peeling member is twisted in the direction of correcting the inclination at the other end in the longitudinal direction with the one end in the longitudinal direction as a fulcrum. By this correction, the distance between the surface of one rotating member and the peeling member becomes constant in the longitudinal direction. After fixing at the nip portion, the paper wound around the surface of one of the rotating members is peeled off from the surface by the peeling member in this state.

  Further, in the invention according to claim 2, the release member includes a release sheet having a distal end adjacent to the surface and extending in the longitudinal direction, and a release sheet holding plate holding the release sheet and extending in the longitudinal direction. And the adjustment member fixes the release sheet holding plate on one end side in the longitudinal direction and rotatably supports the release sheet holding plate on the other end side in the longitudinal direction, and the other end side in the longitudinal direction. And a screw member that is screwed to the release sheet holding plate, and an abutting member that is provided on the shaft member and that can freely come into contact with the screw member by its extension. According to this configuration, even if the release sheet or the release sheet holding plate is inclined in the longitudinal direction, when the screw member is extended and the screw member is brought into contact with the contact member, the release sheet holding plate is supported at one end in the longitudinal direction. Then, it is twisted in the direction of correcting the inclination around the shaft member at the other end in the longitudinal direction. By this correction, the distance between the surface of the one rotary member and the release sheet becomes constant in the longitudinal direction. After fixing at the nip portion, the sheet wound around the surface of one of the rotating members is peeled off from the surface by the release sheet in this state.

  The invention according to claim 3 is characterized in that the pair of screw members are disposed on opposite sides of the shaft member. According to this configuration, when one screw member is extended and this screw member is brought into contact with the contact member, the release sheet holding plate is rotated around the shaft member at the other end in the longitudinal direction with the one end in the longitudinal direction as a fulcrum. Twisted in one direction. Further, when the other screw member is extended and this screw member is brought into contact with the contact member, the release sheet holding plate is moved in the other direction around the shaft member at the other end in the longitudinal direction with the one end in the longitudinal direction as a fulcrum. Twisted. Depending on the direction of the inclination of the peeling member, the inclination of the peeling member is corrected by feeding one of the pair of screw members.

  Further, in the invention according to claim 4, it is provided with a pair of space members that are urged to contact the longitudinal end of the one rotating member and form a predetermined interval between the release sheet and the surface, The pair of space members are fixed to the release sheet holding plate. According to this configuration, when the release sheet holding plate is twisted in the direction of correcting the inclination around the shaft member on the other end side in the longitudinal direction with the one end side in the longitudinal direction as a fulcrum, the release sheet holding plate peels from the surface of one rotating member. The distance between the sheet and the sheet becomes constant in the longitudinal direction, and the pair of space members abut against each other at both ends of one rotating member with a uniform force.

  The invention according to claim 5 is characterized in that the peeling member is disposed along a longitudinal direction of the heating rotating member.

  The invention according to claim 6 is characterized in that the peeling member is disposed along a longitudinal direction of the pressure rotating member.

  According to a seventh aspect of the present invention, there is provided an image forming apparatus equipped with the fixing device having the above configuration.

  According to the first aspect of the present invention, even if the peeling member is deformed from a predetermined shape due to torsion or the like in the manufacturing process and is inclined in the longitudinal direction of the peeling member, the peeling is performed by the adjusting member in a direction to correct the inclination. When the member is swung, the peeling member is twisted in the direction of correcting the inclination at the other end in the longitudinal direction with the one end in the longitudinal direction as a fulcrum. By this correction, the distance between the surface of one rotating member and the peeling member becomes constant in the longitudinal direction. After fixing at the nip portion, the peeling member in this state reliably peels off the paper wound around the surface of the one rotating member from the surface, and does not damage the surface of the one rotating member.

  According to the second aspect of the present invention, when the release sheet or the release sheet holding plate is inclined in the longitudinal direction, when the screw member is extended and the screw member is brought into contact with the contact member, the release sheet holding plate is Then, it is twisted in the direction of correcting the inclination around the shaft member at the other end in the longitudinal direction with the one end in the longitudinal direction as a fulcrum. By this correction, the distance between the surface of the one rotary member and the release sheet becomes constant in the longitudinal direction. After fixing at the nip portion, the release sheet in this state ensures that the paper wound around the surface of one rotating member is reliably peeled off from the surface, and the surface of one rotating member is not damaged.

  According to the invention described in claim 3, when one screw member is extended and this screw member is brought into contact with the contact member, the release sheet holding plate is moved in the longitudinal direction or the like with one end in the longitudinal direction as a fulcrum. It is twisted in one direction around the shaft member on the end side. Further, when the other screw member is extended and this screw member is brought into contact with the contact member, the release sheet holding plate is moved in the other direction around the shaft member at the other end in the longitudinal direction with the one end in the longitudinal direction as a fulcrum. Twisted. By extending one of the pair of screw members according to the direction of the inclination of the peeling member, the inclination of the peeling member is corrected, and the distance between the surface of the one rotating member and the peeling sheet becomes constant in the longitudinal direction. After fixing at the nip portion, the release sheet in this state ensures that the paper wound around the surface of one rotating member is reliably peeled off from the surface, and the surface of one rotating member is not damaged.

  According to the invention described in claim 4, when the release sheet holding plate is twisted in the direction of correcting the inclination around the shaft member at the other end in the longitudinal direction with the one end in the longitudinal direction as a fulcrum, The distance between the surface of the rotating member and the release sheet is constant in the longitudinal direction, and the paper wound around the surface of one rotating member is reliably peeled from the surface. In addition, since the pair of space members abut against each other at both ends of the one rotating member with a uniform force, there is no fear that one end side of the one rotating member is excessively rubbed, and the durability of the one rotating member is improved. improves.

  According to the fifth aspect of the present invention, the paper wound around the surface of the heating rotary member is reliably peeled off from the surface, and the surface of the heating rotary member is not damaged.

  According to the sixth aspect of the present invention, even when the back surface is fixed at the time of double-sided printing, or in the configuration in which the pressure rotating member is disposed below the heating rotating member, The wound paper is reliably peeled off from the surface and the surface of the pressure rotating member is not damaged.

  According to the seventh aspect of the present invention, there is provided an image forming apparatus including a fixing device that reliably peels off the paper attached to the heating rotary member or the pressure rotary member and does not damage the rotary member. can do.

1 is a plan view showing a schematic configuration of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a plan view showing a schematic configuration of a fixing device used in the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a perspective view showing a peeling member of the fixing device according to the first embodiment of the present invention. These are perspective views which show the one end part side of the peeling member of the fixing device which concerns on 1st Embodiment of this invention. These are perspective views which show the other end part side of the peeling member of the fixing device according to the first embodiment of the present invention. These are the partially sectional top views which show the peeling member adjusted of the fixing device which concerns on 1st Embodiment of this invention. These are plan views showing a schematic configuration of a fixing device used in an image forming apparatus according to a second embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Further, the use of the invention and the terms shown here are not limited thereto.

(First embodiment)
FIG. 1 is a plan view schematically showing an internal configuration of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 1 is a tandem type color printer. As the photosensitive members 11a to 11d that are rotatable, an organic photosensitive member (OPC photosensitive member) is used as a photosensitive material for forming a photosensitive layer, and black (B), It is arranged corresponding to each color of yellow (Y), cyan (C) and magenta (M). The photosensitive layer may be amorphous silicon. Around each of the photoreceptors 11a to 11d, developing devices 2a to 2d, an exposure unit 12, chargers 13a to 13d, and static eliminators 14a to 14d are disposed.

  The developing devices 2a to 2d are arranged to face the right sides of the photoconductors 11a to 11d, and supply toner to the photoconductors 11a to 11d. The chargers 13a to 13d are arranged on the upstream side of the developing device 2a to 2d in the rotation direction of the photoconductor and to face the surfaces of the photoconductors 11a to 11d, and uniformly charge the surfaces of the photoconductors 11a to 11d. The static eliminators 14a to 14d are disposed downstream of the developing devices 2a to 2d in the direction of rotation of the photoconductor and face the surfaces of the photoconductors 11a to 11d, and neutralize charges remaining on the surfaces of the photoconductors 11a to 11d after development. To do.

  The exposure unit 12 scans and exposes each of the photoconductors 11a to 11d based on image data such as characters and patterns input from a personal computer or the like to an image input unit (not shown). The developing device 2a ˜2d is provided so as to irradiate light from the downstream side of the chargers 13a to 13d in the photosensitive member rotation direction. The exposure unit 12 is provided with a laser light source and a polygon mirror, and a reflection mirror and a lens are provided corresponding to each of the photoreceptors 11a to 11d. Laser light emitted from the laser light source is applied to the surfaces of the photoconductors 11a to 11d via a polygon mirror, a reflection mirror, and a lens, and the surfaces of the photoconductors 11a to 11d are electrostatically applied to the surfaces of the photoconductors 11a to 11d. A latent image is formed. The electrostatic latent images are developed into toner images by the developing devices 2a to 2d.

  The intermediate transfer belt 17 is stretched around a driving roller 25, a driven roller 27, and a tension roller 6. The photoreceptors 11a to 11d are arranged to face each other below the intermediate transfer belt 17 so as to be in contact with the intermediate transfer belt 17 and to be adjacent to each other along the transport direction (the arrow direction in FIG. 1). The primary transfer rollers 26a to 26d are pressed against the intermediate transfer belt 17 so as to face the photoconductors 11a to 11d with the intermediate transfer belt 17 interposed therebetween, thereby forming a primary transfer nip portion. In each primary transfer nip portion, the toner images on the photoreceptors 11a to 11d are sequentially transferred to the intermediate transfer belt 17 at a predetermined timing as the intermediate transfer belt 17 rotates. As a result, four color toner images of cyan, magenta, yellow, and black are superimposed on the surface of the intermediate transfer belt 17 to form a color toner image. The belt cleaning 31 cleans the toner remaining on the intermediate transfer belt 17 after the transfer.

  The secondary transfer roller 34 is opposed to the drive roller 25 with the intermediate transfer belt 17 interposed therebetween, and presses against the intermediate transfer belt 17 to form a secondary transfer nip portion. In the secondary transfer nip portion, the toner image formed on the intermediate transfer belt 17 is secondarily transferred onto the sheet by the secondary transfer roller 34 to which a bias potential (a polarity opposite to the toner charging polarity) is applied.

  A paper feed cassette 32 that stores paper P is disposed below the image forming apparatus 1, and a stack tray 35 that supplies manual paper is disposed on the right side of the paper feed cassette 32. On the left side of the paper feed cassette 32, a first transport path 33 for transporting the paper P fed from the paper feed cassette 32 to the secondary transfer nip portion is disposed. Further, on the left side of the stack tray 35, a second transport path 36 for transporting the sheet fed from the stack tray 35 to the secondary transfer nip portion is provided. In the upper left part of the image forming apparatus 1, a fixing device 18 that performs a fixing process on the paper P to which the toner image has been transferred, and a third transport path that transports the paper P on which the fixing process has been performed to the paper discharge unit 37. 39 is disposed.

  The paper feed cassette 32 can be replenished by pulling it out of the apparatus (drawn to the front side in FIG. 1). The paper P stored therein is picked up by the pickup roller 33b and the separating roller 33a one by one. It is fed out to the first conveyance path 33 side.

  The first conveyance path 33 and the second conveyance path 36 are merged before the registration roller 33c, and the registration roller 33c takes the timing of the image forming operation and the sheet feeding operation at the secondary transfer nip portion, and the sheet P is conveyed to the secondary transfer nip portion. The sheet P conveyed to the secondary transfer nip portion is transferred with the toner image on the intermediate transfer belt 17 and conveyed to the fixing device 18.

  The fixing device 18 includes a fixing belt heated by a heater, a pressure roller disposed in pressure contact with the fixing belt, and the like, and performs fixing processing by heating and pressing the paper P on which the toner image is transferred. Do. The fixed paper P is reversed in the fourth conveyance path 40 as necessary, and a toner image is transferred to the back surface of the paper at the secondary transfer nip portion, and is fixed again by the fixing device 18, and the paper is discharged by the discharge roller 19a. It is discharged to the discharge unit 37.

  The fixing device 18 will be described in detail. FIG. 2 is a plan view showing a schematic configuration of a fixing device used in the image forming apparatus 1 described above.

  The fixing device 18 is a belt fixing system, and includes a pressure roller 54 that is a pressure rotating member, an endless fixing belt 52 that is a heating rotating member, a fixing roller 53 included in the fixing belt 52, A heat roller 55 that stretches the fixing belt 52 together with the fixing roller 53, a heater lamp 55 a as a heat source included in the heat roller 55, and a peeling member 60 and a space member 80 are further provided.

  The fixing roller 53, the pressure roller 54, and the heat roller 55 are pivotally supported by a housing (not shown) so as to be rotatable in the longitudinal direction of the fixing device 18 (a direction orthogonal to the sheet conveying direction), and a heater lamp 55a and a peeling member. Reference numeral 60 denotes a housing (not shown), and the space member 80 is fixedly held to the peeling member 60.

  The pressure roller 54 is in pressure contact with the fixing roller 53 via the fixing belt 52, and a nip portion N is formed at a portion where the fixing belt 52 and the pressure roller 54 abut.

  The heat roller 55 is formed of a cylindrical aluminum tube. Heat from the included heater lamp 55a is transmitted to the fixing belt 52 through the heat roller 55, and the fixing belt 52 is heated.

  The fixing belt 52 is formed of a nickel thin plate and imparts flexibility to the fixing belt 52. An elastic layer such as silicon rubber is formed on the outer surface to give elasticity to the fixing belt 52. Further, a release layer such as a fluororesin is laminated to melt and fix the unfixed toner image at the nip N. Improve releasability at the time.

  The fixing roller 53 is made of stainless steel and includes an elastic layer such as sponge rubber on a cylindrical base material, and imparts elasticity to the nip portion N.

  The pressure roller 54 covers an elastic layer such as silicon rubber on a cylindrical base material made of synthetic resin, metal or other material, and gives elasticity to the nip portion N. Further, a release layer made of a fluorine resin or the like is provided on the surface of the pressure roller 54 to improve the release property when the unfixed toner image is melted and fixed at the nip portion N.

  The pressure roller 54 is rotationally driven in the arrow direction (counterclockwise direction) in FIG. 2 by a drive source (not shown) such as a motor. The rotation of the pressure roller 54 causes the fixing roller 53 and the fixing belt 52 that are in pressure contact with the pressure roller 54 to rotate at the same speed in the arrow direction (clockwise direction) shown in FIG. 2, and the heat roller 55 is driven by the fixing belt 52. Rotate. The heat from the heater lamp 55a disposed in the hollow of the heat roller 55 is transmitted to the fixing belt 52 through the heat roller 55, and the fixing belt 52 is heated, so that the pressure roller 54 and the fixing belt 52 are mutually connected. The paper P is conveyed to the upper side of the apparatus while the toner image of the paper P is heated and melted at the nip portion N by the reverse rotation of the sheet P. Instead of the configuration in which the pressure roller 54 is rotated by a driving source such as a motor, the fixing roller 53 or the heat roller 55 is rotated by a driving source such as a motor, and the pressure roller 54 is further rotated. Also good.

  The peeling member 60 is disposed in the vicinity of the nip portion N on the downstream side in the belt rotation direction of the nip portion N of the fixing belt 52. When the leading end of the peeling member 60 is disposed close to the surface of the fixing belt 52 and the paper P is wound around the surface of the fixing belt 52 after fixing, the peeling member 60 is separated from the wound paper P by the leading end. The tip is peeled off from the surface of the fixing belt 52.

  The peeling member 60 will be described in detail with reference to FIGS. 3 is a perspective view showing a peeling member to which a space member and an adjustment member are attached, FIG. 4 is a perspective view showing one end portion side of the peeling member, and FIG. 5 is a perspective view showing the other end portion side of the peeling member. FIG. 4 and 5 show the peeling member from which the space member has been removed. FIG. 6 is a partially cross-sectional plan view showing the peeling member to be adjusted.

  As shown in FIG. 3, the release member 60 includes a release sheet 61 and a release sheet holding plate 62. Adjustment members 70 are disposed on both ends of the peeling member 60 in the longitudinal direction, and the adjustment member 70 includes a shaft member 71, a pair of screw members 72 and 73, and a contact member 76. A pair of space members 80 and springs 81 are disposed on both end sides in the longitudinal direction of the peeling member 60.

  The release sheet 61 is formed of a rectangular stainless steel plate extending in the longitudinal direction, and a front end 61a extending in the longitudinal direction is opposed to the surface of the fixing belt 52 (see FIG. 6). The release sheet 61 is formed of stainless steel having a thickness of 0.2 to 0.3 mm. However, the release sheet 61 may be formed of a synthetic resin if the thickness is substantially the same.

  The release sheet holding plate 62 is formed of a stainless steel plate thicker than the release sheet 61, and is formed with a sheet holding surface 62a formed of a substantially rectangular plane extending in the longitudinal direction, and one end side in the longitudinal direction of the sheet holding surface 62a. Is bent into an L shape, and a bent portion 62d is formed by bending the other end in the longitudinal direction into an L shape.

  The release sheet 61 is fixed and held on the sheet holding surface 62a by spot welding. A pair of screw members 72 and 73 are screwed to the other end in the longitudinal direction of the sheet holding surface 62a. When the release sheet 61 is a synthetic resin, the release sheet 61 is fixedly held on the sheet holding surface 62a by ultrasonic welding.

  Holes are formed in the bent portions 62b and 62d, and both end portions of the shaft member 71 are fitted in the holes of the bent portions 62b and 62d.

  The pair of space members 80 are respectively disposed between the end portion in the longitudinal direction of the release sheet 61 and the bent portions 62b and 62d. One end of the space member 80 is fixed to the sheet holding surface 62a, and the other end is formed in a cylindrical shape. The other end of the cylindrical shape is in contact with the fixing belt 52 (see FIG. 2), and smoothly slides against the rotating fixing belt 52 outside the fixing region of the paper P. It should be noted that the other end of the cylindrical shape may be a rotatable roller and abut on the fixing belt 52.

  The spring 81 urges the space member 80, and the urging force always brings the other end of the cylindrical shape of the space member 80 into contact with the surface of the fixing belt 52. As a result, a gap is formed between the front end 61a of the release sheet 61 and the surface of the fixing belt 52 (see FIG. 6).

  The one end side of the peeling member 60 will be described in detail with reference to FIG. 4. As described above, the shaft member 71 is fitted in the hole of the bent portion 62b of the peeling sheet holding plate 62. An oval shaft 62b that fits into the oval hole 62c is formed at the end of the shaft member 71. When the oval shaft 71b is fitted into the oval hole 62c, the shaft member 71 and the bent portion 62b cannot be relatively rotated.

  Next, the other end portion side of the peeling member 60 will be described in detail with reference to FIG. 5. As described above, the shaft member 71 is fitted in the hole of the bent portion 62d of the peeling sheet holding plate 62. It is a round hole 62e, and the rotating shaft 71e which fits in this round hole 62e is formed in the edge part of the shaft member 71. As shown in FIG. The outer diameter of the rotating shaft 71e is the same size as the outer diameter of the shaft member 71, and when the rotating shaft 71e is fitted into the round hole 62e, the shaft member 71 and the bent portion 62d rotate relatively around the rotating shaft 71e. Is possible. Therefore, when a rotational force greater than the rigidity of the release sheet holding plate 62 is applied around the rotation shaft 71e of the bent portion 62d, the small hole 62c is fitted to the small shaft 71b on one end side (see FIG. 4). Since the bent portion 62b is fixed, the sheet holding surface 62a in the vicinity of the bent portion 62b is not deformed, and even if it is deformed, it is slight. On the other hand, since the other end portion extends in the longitudinal direction from the bent portion 62b, the sheet holding surface 62a in the vicinity of the bent portion 62d is greatly deformed by the rotational force as compared with the sheet holding surface 62a in the vicinity of the bent portion 62b. It will be. That is, the sheet holding surface 62a is torsionally deformed in the direction in which the rotational force acts with the other end portion as a fulcrum.

  A pair of screw holes 62 f are formed in the sheet holding surface 62 a of the release sheet holding plate 62. A screw member 72 is screwed into one screw hole 62f, and a screw member 73 is screwed into the other screw hole 62f (see FIG. 6). The pair of screw holes 62f are arranged on opposite sides of the round hole 62e.

  An abutting member 76 is disposed opposite to the screw members 72 and 73. The abutting member 76 is a rectangular plate material, and is fixed to the shaft member 71 by a mounting screw 82. The contact member 76 may be formed integrally with the shaft member 71.

  As shown in FIG. 6, the screw member 72 has a screw portion 72a, a screw head portion 72b, and a screw tip portion 72c. When the screw head 72b is rotated, the screw member 72 is drawn out by the screw portion 72a screwed into the screw hole 62f, and the screw tip portion 72c contacts the contact surface 76a of the contact member 76 as shown in FIG. You can touch. When the screw head 72b is rotated in the reverse direction, the screw member 72 is fed out in the reverse direction by the screw portion 72a, and the screw tip portion 72c is separated from the contact surface 76a.

  The screw member 73 disposed on the opposite side of the screw member 72 with respect to the shaft member 71 has a screw portion 73a, a screw head portion 73b, and a screw tip portion 73c. When the screw head 73b is rotated, the screw member 73 is drawn out toward the contact surface 76a by the screw portion 73a that is screwed into the screw hole 62f, and the screw tip 73c can contact the contact surface 76a. When the screw head portion 73b is rotated in the reverse direction, the screw member 73 is fed out in the reverse direction by the screw portion 73a, and the screw tip portion 73c is separated from the contact surface 76a.

  Here, when the screw head 72b is further rotated while the screw tip 72c is in contact with the contact surface 76a, the screw tip 72c is in contact with the contact surface 76a. The sheet holding surface 62a in which the screw hole 62f is formed moves to the screw head 72b side by the portion 72a. This movement of the sheet holding surface 62a is that the release sheet holding plate 62 rotates in the counterclockwise direction of FIG. 6 around the rotation axis 71e, and the leading end portion 61a of the release sheet 61 is indicated by a one-dot chain line from the solid line position of FIG. As shown by the arrow, the belt moves in a direction approaching the surface of the fixing belt 52. On the other hand, on one end side (see FIG. 4), the oval hole 62c fits into the oval shaft 71b and the bent portion 62b is fixed, so the sheet holding surface 62a in the vicinity of the bent portion 62b does not move. That is, the tip 61a on the one end side is at the position of the solid line in FIG. 6, the tip 61a on the other end is at the one-dot chain line in FIG. 6, and the tip 61a from the one end to the other end is shown by the solid line The torsional deformation is performed so that the inclination can be gradually changed between the position and the alternate long and short dash line position.

  On the other hand, when the screw tip portion 72c is separated from the contact surface 76a, and the screw head portion 73b is further rotated while the screw tip portion 73c of the screw member 73 is in contact with the contact surface 76a, the sheet holding surface 62a is moved. It moves to the screw head 73b side. This movement of the sheet holding surface 62a is that the release sheet holding plate 62 rotates in the clockwise direction of FIG. 6 around the rotation axis 71e, and the leading end 61a of the release sheet 61 is indicated by a broken line from the solid line position of FIG. In this way, it moves away from the surface of the fixing belt 52. On the other hand, on one end side (see FIG. 4), the oval hole 62c fits into the oval shaft 71b and the bent portion 62b is fixed, so the sheet holding surface 62a in the vicinity of the bent portion 62b does not move. That is, the tip 61a on the one end side is at the solid line position in FIG. 6, the tip 61a on the other end side is in the broken line position in FIG. 6, and the tip 61a from the one end to the other end is in the solid line position. And torsional deformation so that the inclination can be gradually changed between the broken line positions.

  Since the sheet holding surface 62a of the release sheet 61 or the release sheet holding plate 62 extends in the longitudinal direction, the flatness is lost during manufacturing, and the inclination of the surface is particularly likely to occur in the longitudinal direction. Here, assembly adjustment for correcting the inclination of the sheet holding surface 62a and the release sheet 61 will be described with reference to FIGS.

  The shaft member 71 is assembled to the release sheet holding plate 62. The screw members 72 and 73 are assembled to the release sheet holding plate 62 in a state where the contact member 76 is not contacted. The space member 80 is assembled to the release sheet holding plate 62. The peeling member 60 to which the adjusting member 70 and the space member 80 are attached is attached to a housing (not shown). At this time, both end portions of the shaft member 71 are rotatably held by the housing. When the spring 81 is attached between the space member 80 and the housing, the space member 80 is always in contact with the surface of the fixing belt 52 by the biasing force of the spring 81. Here, if the sheet holding surface 62a or the release sheet 61 is inclined, the distance between the tip 61a of the release sheet 61 and the surface of the fixing belt 52 is not constant in the longitudinal direction. This interval is measured by a gap gauge corresponding to a predetermined interval. Alternatively, it is measured by a laser length measuring device.

  As a result of this measurement, when the other end side in the longitudinal direction is larger than the predetermined interval, the screw head 72b of the screw member 72 is rotated, and the screw tip 72c is drawn out so as to contact the contact surface 76a. While the screw tip 72c is in contact with the contact surface 76a, the screw head 72b is further rotated while measuring the gap between the tip 61a and the surface of the fixing belt 52 until the gap becomes constant in the longitudinal direction. Let

  On the other hand, when the other end side in the longitudinal direction is smaller than the predetermined interval, the screw head 73b of the screw member 73 is rotated, and the screw tip 73c is drawn out so as to contact the contact surface 76a. While the screw tip 73c is in contact with the contact surface 76a, the screw head 73b is further rotated until the gap becomes constant in the longitudinal direction while measuring the gap between the tip 61a and the surface of the fixing belt 52. Let

  Thus, the peeling member 60 in which the distance between the peeling sheet 61 and the surface of the fixing belt 52 is constant in the longitudinal direction is disposed so as to be inclined toward the nip portion N in FIG.

  When image formation is performed, the paper P to which the toner image T has been transferred is conveyed in the arrow Y direction from the pre-fixing guide 21 disposed on the upstream side of the fixing belt 52 in the paper conveyance direction, and heated at the nip portion N. The toner image T is fixed on the paper P by being pressed. At this time, the paper P attached and wound around the fixing belt 52 is peeled off by the peeling member 60. Thereafter, the paper P is discharged to the paper discharge section by the post-fixing guide 22 and the transport rollers 23a and 23b arranged on the downstream side in the paper transport direction.

  According to the first embodiment, the fixing device 18 is formed by the fixing belt 52 heated by the heater lamp 55a, the pressure roller 54 pressed against the fixing belt 52, the fixing belt 52, and the pressure roller 54. And a nip portion N for fusing and fixing the toner image transferred to the paper P. Further, the fixing device 18 has a gap with the surface of the fixing belt 52 and is disposed along the longitudinal direction on the downstream side in the rotation direction of the fixing belt 52, and one longitudinal end of the peeling member 60. And an adjusting member 70 that is provided so that the other end in the longitudinal direction of the peeling member 60 can swing with respect to the surface of the fixing belt 52.

  According to this configuration, even if the peeling member 60 is deformed from a predetermined shape due to torsion or the like in the manufacturing process or the like and tilts in the longitudinal direction of the peeling member 60, the peeling member 60 is adjusted in the direction to correct the tilt. The separation member 60 is twisted in the direction of correcting the inclination at the other end in the longitudinal direction with the one end in the longitudinal direction as a fulcrum. By this correction, the distance between the surface of the fixing belt 52 and the peeling member 60 becomes constant in the longitudinal direction. After fixing at the nip portion N, the sheet P wound around the surface of the fixing belt 52 is surely separated from the surface by the peeling member 60 in this state, and the fixing belt 52 is not damaged.

  In addition, according to the first embodiment, the peeling member 60 includes the peeling sheet 61 having the leading end 61a approaching the surface of the fixing belt 52 and extending in the longitudinal direction, and holding the peeling sheet 61 and extending in the longitudinal direction. And a release sheet holding plate 62. The adjustment member 70 fixes the release sheet holding plate 62 on one end side in the longitudinal direction and rotatably supports the release sheet holding plate 62 on the other end side in the longitudinal direction, and holds the release sheet on the other end side in the longitudinal direction. Screw members 72 and 73 that are screwed into the plate 62 and a contact member 76 that is provided on the shaft member 71 and that can contact the screw members 72 and 73 by being extended. Thus, even if the release sheet 61 or the release sheet holding plate 62 is inclined in the longitudinal direction, when the screw members 72 and 73 are extended and the screw members 72 and 73 are brought into contact with the contact member 76, the release sheet holding plate 62 is Then, it is twisted in the direction of correcting the inclination around the shaft member on the other end side in the longitudinal direction with the one end side in the longitudinal direction as a fulcrum. By this correction, the distance between the surface of the fixing belt 52 and the release sheet 61 becomes constant in the longitudinal direction. After fixing at the nip N, the sheet P wound around the surface of the fixing belt 52 is surely peeled off from the surface by the release sheet 61 in this state, and the surface of the fixing belt 52 is not damaged.

  Further, according to the first embodiment, the pair of screw members 72 and 73 are disposed on the opposite sides with respect to the shaft member 71. Accordingly, when one screw member 72 is extended and this screw member 72 is brought into contact with the contact member 76, the release sheet holding plate 62 rotates around the shaft member at the other end in the longitudinal direction with the one end in the longitudinal direction as a fulcrum. Twisted in one direction. Further, when the other screw member 73 is extended and this screw member 73 is brought into contact with the contact member 76, the release sheet holding plate 62 is rotated around the shaft member at the other end in the longitudinal direction with the one end in the longitudinal direction as a fulcrum. Twisted in the other direction. Depending on the inclination direction of the sheet holding surface 62a of the release sheet holding plate 62, the inclination of the sheet holding surface 62a is corrected by extending one of the pair of screw members 72 and 73, and the surface of the fixing belt 52 and the release sheet The distance from 61 is constant in the longitudinal direction. After fixing at the nip N, the sheet P wound around the surface of the fixing belt 52 is surely peeled off from the surface by the release sheet 61 in this state, and the surface of the fixing belt 52 is not damaged.

  In addition, according to the first embodiment, it is provided with a pair of space members 80 that are urged to contact the longitudinal end of the fixing belt 52 and form a predetermined interval on the surface of the release sheet 61 and the fixing belt 52. The space member 80 is fixed to the release sheet holding plate 62. Thus, when the release sheet holding plate 62 is twisted in the direction of correcting the inclination around the shaft member on the other end side in the longitudinal direction with the one end side in the longitudinal direction as a fulcrum, the surface of the fixing belt 52 and the release sheet 61 are Is constant in the longitudinal direction, and the paper P wound around the surface of the fixing belt 52 is reliably peeled off from the surface. Further, since the pair of space members 80 abut against both ends of the fixing belt 52 with a uniform force, there is no possibility that one end side of the fixing belt 52 is rubbed excessively, and the durability of the fixing belt 52 is improved. .

(Second Embodiment)
FIG. 7 is a plan view showing a schematic configuration of a fixing device used in the image forming apparatus according to the second embodiment of the present invention. The fixing method and the arrangement of the peeling member, which are different from those in the first embodiment, will be mainly described.

  The fixing device 18 is a roller fixing system, and includes a pressure roller 154 that is a pressure rotating member, a heating roller 153 that is a heating rotating member, a heater lamp 153 a as a heat source contained in the heating roller 153, a first The peeling member 60 and the space member 80 which are the same structure effects as embodiment are provided.

  The pressure roller 154 is disposed immediately below the heating roller 153, and the heating roller 153 and the pressure roller 154 are provided in a casing (not shown) so as to be rotatable in the longitudinal direction of the fixing device 18 (direction perpendicular to the sheet conveying direction). It is pivotally supported. The heater lamp 153a and the peeling member 60 are held by a housing (not shown), and the space member 80 is fixedly held by the peeling member 60. The peeling member 60 is adjusted so that the distance between the tip of the peeling member 60 and the surface of the pressure roller 154 is constant in the longitudinal direction.

  The heating roller 153 includes an elastic layer such as sponge rubber on a cylindrical base material made of stainless steel, and a release layer made of a fluororesin or the like on the surface layer. The pressure roller 154 covers an elastic layer such as silicon rubber on a cylindrical base material made of synthetic resin, metal, or other material, and a release layer made of fluorine resin or the like on the surface of the pressure roller 154. Is provided. The pressure roller 154 comes into pressure contact with the heating roller 153, and a nip portion N is formed at a portion where the heating roller 153 and the pressure roller 154 come into contact with each other.

  The pressure roller 154 is rotationally driven in the arrow direction (counterclockwise direction) in FIG. 7 by a drive source (not shown) such as a motor. The rotation of the pressure roller 154 causes the heating roller 153 that is in pressure contact with the pressure roller 154 to rotate at the same speed in the direction of the arrow in FIG. 7 (clockwise direction). Since the heating roller 153 is heated by the heater lamp 153a disposed in the hollow of the heating roller 153, the toner image on the paper P is transferred at the nip portion N by the reverse rotation of the pressure roller 154 and the heating roller 153. The sheet P is conveyed to the left of the nip portion N while being heated and melted. Instead of the configuration in which the pressure roller 154 is rotationally driven by a driving source such as a motor, the heating roller 153 may be rotationally driven by a driving source such as a motor.

  The peeling member 60 is disposed in the vicinity of the nip portion N on the downstream side of the nip portion N in the rotation direction of the pressure roller. When the leading end of the peeling member 60 is disposed close to the surface of the pressure roller 154 and the paper P is wound around the surface of the pressure roller 154 after fixing, the peeling member 60 is wound around the paper by the leading end. The tip of P is peeled off from the pressure roller 154 surface.

  One end of the space member 80 is fixed to the peeling member 60. The other end of the space member 80 is formed in a cylindrical shape, contacts the pressure roller 154, and smoothly slides against the rotating pressure roller 154 outside the fixing region of the paper P. Note that the other end of the cylindrical shape may be a rotatable roller and may be in contact with the pressure roller 154.

  The paper P to which the toner image T has been transferred is heated and pressed at the nip N, whereby the toner image T is fixed to the paper P. At this time, when heat-fixing the back surface of double-sided printing, the toner on the surface of the paper P is melted, and the paper P conveyed from the nip portion N hangs on the pressure roller 154 due to its gravity. May adhere to the pressure roller 154. Thus, the paper P attached and wound around the pressure roller 154 is peeled off by the leading end portion of the peeling member 60. In order to prevent the sheet P having the surface fixed from being wound around the heating roller 153, the peeling member 60 and the space member 80 may be disposed on the downstream side in the rotation direction of the nip portion N of the heating roller 153. .

  According to the second embodiment, the fixing device 18 is formed by the heating roller 153 heated by the heater lamp 153 a, the pressure roller 154 that presses against the heating roller 153, the heating roller 153, and the pressure roller 154. And a nip portion N for fusing and fixing the toner image transferred to the paper P. Further, the fixing device 18 has a gap with the surface of the heating roller 153 and is disposed along the longitudinal direction on the downstream side in the rotation direction of the heating roller 153, and one end in the longitudinal direction of the peeling member 60. And an adjustment member 70 that is provided so that the other end in the longitudinal direction of the peeling member 60 can swing with respect to the surface of the heating roller 153.

  According to this configuration, even if the peeling member 60 is deformed from a predetermined shape due to torsion or the like in the manufacturing process or the like and tilts in the longitudinal direction of the peeling member 60, the peeling member 60 is adjusted in the direction to correct the tilt. The separation member 60 is twisted in the direction of correcting the inclination at the other end in the longitudinal direction with the one end in the longitudinal direction as a fulcrum. By this correction, the distance between the surface of the heating roller 153 and the peeling member 60 becomes constant in the longitudinal direction. After fixing at the nip portion N, the sheet P wound around the surface of the heating roller 153 is surely separated from the surface by the peeling member 60 in this state, and the heating roller 153 is not damaged.

  Further, according to the second embodiment, the fixing device 18 is formed by the heating roller 153 heated by the heater lamp 153a, the pressure roller 154 pressed against the heating roller 153, the heating roller 153, and the pressure roller 154. And a nip portion N for fusing and fixing the toner image transferred onto the paper P. Further, the fixing device 18 has a gap with the surface of the pressure roller 154 and is disposed along the longitudinal direction on the downstream side in the rotation direction of the pressure roller 154, and the longitudinal direction of the peeling member 60. One end in the direction is fixed, and the other end in the longitudinal direction of the peeling member 60 is provided with an adjustment member 70 provided to be swingable with respect to the pressure roller 154 surface.

  According to this configuration, even if the peeling member 60 is deformed from a predetermined shape due to torsion or the like in the manufacturing process or the like and tilts in the longitudinal direction of the peeling member 60, the peeling member 60 is adjusted in the direction to correct the tilt. The separation member 60 is twisted in the direction of correcting the inclination at the other end in the longitudinal direction with the one end in the longitudinal direction as a fulcrum. By this correction, the distance between the surface of the pressure roller 154 and the peeling member 60 becomes constant in the longitudinal direction. After fixing at the nip portion N, the sheet P wound around the surface of the pressure roller 154 is surely separated from the surface by the peeling member 60 in this state, and the pressure roller 154 is not damaged.

  INDUSTRIAL APPLICABILITY The present invention can be used for a fixing device used in an image forming apparatus such as a copying machine, a printer, a facsimile, and a composite machine using the electrophotographic method, and an image forming apparatus including the fixing device. The present invention can be used for a fixing device including a peeling member that peels off a sheet conveyed from the printer and an image forming apparatus including the fixing device.

1 Image Forming Device 18 Fixing Device 52 Fixing Belt (Heating Rotating Member)
53 Fixing Rollers 54, 154 Pressure Roller (Pressure Rotating Member)
55 Heat roller 55a, 153a Heater lamp (heat source)
60 Release member 61 Release sheet 61a Tip 62 Release sheet holding plate 62a Sheet holding surface 62b, 62d Bending portion 62c Oval hole 62e Round hole 62f Screw hole 70 Adjustment member 71 Shaft member 71b Oval shaft 71e Rotating shaft 72, 73 Screw member 72a , 73a Screw portions 72b, 73b Screw heads 72c, 73c Screw tip portion 76 Contact member 76a Contact surface 80 Space member 81 Spring 82 Mounting screw 153 Heating roller (heating rotating member)
N Nip part P Paper T Toner image

Claims (7)

A heating rotating member heated by a heat source;
A pressurizing rotary member in pressure contact with the heating rotary member;
A nip portion that melts and fixes a toner image formed on the heating rotating member and the heating rotating member and transferred to a sheet;
A peeling member that has a gap with the surface of one of the heating rotary member and the pressure rotary member, and is disposed along the longitudinal direction on the downstream side in the rotational direction of the one rotary member;
A fixing device comprising: an adjusting member that fixes one end of the peeling member in the longitudinal direction and is provided such that the other end in the longitudinal direction of the peeling member can swing with respect to the surface.   The release member has a release sheet that has a tip portion close to the surface and extends in the longitudinal direction, and a release sheet holding plate that holds the release sheet and extends in the longitudinal direction. A shaft member that fixes the release sheet holding plate at one end in the direction and rotatably supports the release sheet holding plate at the other end in the longitudinal direction, and a screw that is screwed to the release sheet holding plate at the other end in the longitudinal direction The fixing device according to claim 1, further comprising: a member; and a contact member provided on the shaft member and capable of contacting the screw member by being extended.   The fixing device according to claim 2, wherein the pair of screw members are disposed on opposite sides of the shaft member.   A pair of space members that are urged to contact the longitudinal end of the one rotating member and form a predetermined distance between the release sheet and the surface, the pair of space members being the release sheet holding plate The fixing device according to claim 2, wherein the fixing device is fixed to the fixing device.   The fixing device according to claim 1, wherein the peeling member is disposed along a longitudinal direction of the heating rotation member.   The fixing device according to claim 1, wherein the peeling member is disposed along a longitudinal direction of the pressure rotating member.   An image forming apparatus on which the fixing device according to claim 1 is mounted.

Images